This invention relates generally to fire-resistant ceiling supporting systems and the like and, more particularly to a supporting system for dry wall ceilings capable of absorbing thermal expansion in the system components without substantial buckling or collapsing of the dry wall ceiling during abnormally elevated temperatures, thereby preserving the integrity of the ceiling as a barrier under such conditions.
The present invention is particularly adapted for use in a dry wall ceiling grid system of the type comprising a plurality of parallel spaced main beam or grid members and cross channel support members extending transversely between the main beam members and having end portions interlocking therewith. These interlocked grid members generally are suspended from a conventional ceiling or an overhead support structure.
One of the critical problems encountered in supporting grid structures of the type referred to hereinabove is to maintain the integrity thereof and the associated ceiling under abnormally elevated temperatures, such as accompany a fire. Under these high temperature conditions, the metallic members of the supporting system which generally are fixed at their opposite ends, expand and buckle whereby the supported ceiling panels are displaced and break away to such an extent that they drop to the floor below. As a result, the effectiveness of the suspended ceiling as a barrier is destroyed and the overhead ceiling and related support structure is exposed to the fire whereby the latter can spread more easily and rapidly throughout the entire structure.